LONDON - Britain is considering lifting the six-month quarantine on pets arriving from the United States and Canada, officials said this week -- in part because of pressure from diplomats who do not want to roam without Rover.

"We have been discussing it with the American embassy, but we don't know how long it's going to be," said a spokeswoman for the Department for Environment, Food and Rural Affairs on condition of anonymity.

A century-old law requires animals from most countries to be quarantined for six months upon their arrival in rabies-free Britain.

Two years ago, the government introduced a pet passport plan allowing cats and dogs from western Europe to skip quarantine as long as they have documents confirming their identity and rabies-free status.

The plan was later extended to 50 territories including Australia, New Zealand, Japan and Hawaii.

U.S. officials -- many pet-lovers among them -- want the program to cover the United States as well, said Karen Morrissey, U.S. embassy spokeswoman. She said the embassy's agriculture envoy, Peter Kurz, has met several times with British officials about the issue.

"It's something that the U.S. government has wanted to see happen for a long time," Ms. Morrissey said.

She said studies suggest there is little risk of rabies or other diseases being transmitted by vaccinated North American pets.

More than 40,000 cats and dogs have entered Britain under the passport program, which requires pets to be tagged with an identification microchip, vaccinated and have blood tests done before they travel to Britain.

Rules being considered for pets from North America would be even tighter. Pets would have to be deloused and dewormed and undergo veterinary inspections before and after arrival.

The government spokeswoman said officials were studying academic reports on the risk -- not just from rabies but from parasites such as ringworm and heartworm, which can affect humans.

The government also is awaiting details of a European Union plan to establish a pet passport scheme -- similar to the British one but not limited to cats and dogs -- across the EU. European officials hope to finalize the plan by the end of June.

Some North American pet owners currently send their pets for a six-month holiday in another European country so they can qualify for the pet passport scheme. William Farish, the U.S. Ambassador, has sent his dog to France to wait out its entry clearance, Ms. Morrissey said.

Thousands more must leave beloved pets behind, or subject them to six lonely -- and expensive -- months in quarantine. U.S. officials say some diplomats and others put off moving to Britain as a result.